In a 68-year-old man with newly diagnosed osteoporosis, which is the most common site of fragility fracture?

Explanation

## Common Sites of Osteoporotic Fractures **Key Point:** Vertebral fractures are the most common osteoporotic fractures overall, occurring in approximately 1 in 3 women and 1 in 12 men over age 50. However, hip fractures carry the highest morbidity and mortality. ### Pathophysiology of Vertebral Fracture Predilection 1. **High trabecular bone content** — Vertebral bodies are predominantly trabecular bone (>50%), which has a higher surface area and remodels more rapidly than cortical bone, making it more sensitive to estrogen deficiency and aging. 2. **Mechanical loading** — The thoracolumbar junction (T12–L1) bears significant axial load and is the most common site of vertebral compression fractures. 3. **Age-related changes** — Kyphosis and progressive height loss reflect cumulative vertebral microfractures and compression. ### Frequency of Osteoporotic Fractures | Site | Frequency (% of all OP fractures) | Mechanism | Clinical Significance | | --- | --- | --- | --- | | **Vertebral bodies** | 40–50% | Compression, trabecular collapse | Often asymptomatic, detected on imaging | | **Femoral neck (hip)** | 20–25% | Intracapsular fracture, high-energy trauma | Highest morbidity, mortality, disability | | **Distal radius (Colles)** | 15–20% | Fall on outstretched hand (FOOSH) | Sentinel fracture, early warning sign | | **Proximal humerus** | 5–10% | Fall, low-energy trauma | Less common, better prognosis | **Clinical Pearl:** Vertebral fractures are often **silent** — many patients do not recall a fall or acute trauma. Progressive kyphosis, height loss (>1.5 inches), and back pain may be the only clues. Radiographs or DEXA may reveal multiple compression fractures incidentally. **High-Yield:** The "**fragility fracture triad**" in osteoporosis is: 1. Vertebral compression fractures (most common) 2. Hip fractures (highest morbidity) 3. Distal radius fractures (sentinel event) **Mnemonic: VHR** — **V**ertebral (most common), **H**ip (most serious), **R**adius (sentinel). **Tip:** On NEET PG, if asked "most common site," answer **vertebral**. If asked "most serious" or "highest mortality," answer **hip**. The distinction is critical. [cite:Harrison 21e Ch 397; Robbins 10e Ch 26]